Clamp for industrial truck



Nov. 1, 1955 D. w. GAULT CLAMP FOR INDUSTRIAL TRUCK 5 Sheets-Sheet 1Filed Sept. 8, 1950 FIG. I

INVENTOR. DONALD W. GAULT ATTYS.

Nov. 1, 1955 D. w. GAULT 2,722,327

CLAMP FOR INDUSTRIAL TRUCK Filed Sept. 8, 1950 5 Sheets-Sheet 3INVENTOR.

DONALD w. GAULT W I W ATTYS.

Nov. 1, 1955 D. w. GAULT 2,722,327

CLAMP FOR INDUSTRIAL TRUCK Filed Sept. 8, 1950 5 Sheets-Sheet 4INVENTOR. DONALD W. GAULT ATTYS.

Nov. 1, 1955 D. w. GAULT CLAMP FOR INDUSTRIAL TRUCK 5 Sheets-Sheet 5Filed Sept. 8. 1950 R u m u a m A w W G M u I W "H" 1/ W "I l" h D I hmn N- mm I N mm M w w B6 v Z hlc ms. uNl mm 1 Q \JH l\ P m \T& u E

United States Patent Ofiice 2,722,327 Patented Nov. 1, 1955 CLAMP FORINDUSTRIAL TRUCK Donald W. Gault, Battle Creek, Mich., assignor to ClarkEquipment Company, Buchanan, Mich., a corporation of MichiganApplication September 8, 1950, Serial No. 183,730

8 Claims. 01. 214-653) My invention relates generally to load engagingmeans for industrial trucks, and, more specifically, is directed toclamp means adapted to engage the upper horizontal edge, rim, bead, orchime of a crate or like container.

It is an object of my present invention to provide clamp means which isadapted to be mounted to the load supporting carriage of an industrialtruck for engaging the upper horizontal rim of a container, whereby thelatter may be transported, stacked, and deposited by the industrialtruck. It is another object of my present invention to provide a clampconstruction comprising vertically extending frame means, which definesfixed clamp means, and substantially horizontally movable clamp meansadapted to cooperate with the fixed clamp means for gripping the rim ofa container.

In one form of my present invention, I contemplate the provision ofvertically extending frame means adapted to be secured to the loadsupporting carriage of an industrial truck. A fixed clamp element issecured along the forward surface of the frame means, adjacent the upperend thereof. Disposed adjacent the ends of the frame means aresubstantially horizontally movable clamp elements which are adapted tobe moved toward and away from the fixed clamp element by means ofhorizontal hydraulic piston and cylinder assemblies. pivotally mountedto the frame means. Preferably, substantially vertically downwardlydepending cam members are secured to the movable clamp elements and areadapted to engage ramp members carried by the frame means, whichengagement causes the cam members and movable clamp elements to moveupwardly when the piston rods of the hydraulic piston and cylinderassemblies are extended. Thus, when it is desired to release a crategripped by'the clamp elements, the hydraulic piston and cylinderassemblies are actuated causing the piston rods to be extended which, asdescribed above, effects upward movement of the movable clamp elements,permitting the latter to clear the rim of the crate when the industrialtruck is backed away. When a container or crate is gripped by the clampelements, a portion of the downward force exerted by the weight of aload within the crate or container is taken by the frame means, againstwhich the lower portion of the crate or the container is adapted tobear.

In another and preferredform of my present invention, I contemplate theprovision of a pair of clamp assemblies which are adapted to be securedto the load supporting carriage of an industrial truck, one adjacenteach side thereof. Each clamp assemblycomprises a vertically extendingbox-like frame member, the forward surface of which defines a fixedclamp element. Disposed adjacent the upper end of each of the framemembers is a substantially horizontally movable clamp element which ismoved towardand away from the fixed clamp element by means of ahydraulic pistonand cylinder assembly, operatively connected thereto'byforce transmittingmeans. Both the hydraulic piston and cylinder assemblyand the force transmitting means are disposed within the confines of theframe member. The upper horizontal rim, edge, head, or chime of a crateor like container is adapted to be gripped between the fixed and movablejaw elements. Preferably, an additional auxiliary frame memher ismounted to the load supporting carriage below each of the clampassemblies. When a container is gripped by the clamp elements, a portionof the downward force exerted by the weight of a load within the crateor container is taken by the auxiliary frame members, against which thelower portion of the container is adapted to bear.

Now, in order to acquaint those skilled in the art with the manner ofconstructing and using the devices of my present invention, I shalldescribe, in connection with the accompanying drawings, certainpreferred forms of my invention.

In the drawings:

Figure 1 is a perspective view of an industrial truck to which, at theforward end thereof, is secured one form of clamp construction of mypresent invention;

Figure 2 is a front elevational view of the clamp construction of Figure1;

Figure 3 is a side elevational view of the clamp construction of Figure1;

Figure 4 is a partial plan view of the clamp construction of Figure 1;

Figure 5 is a front elevational view of another and preferred form ofclamp construction of my present invention;

Figure 6 is a side elevational view of the clamp construction of Figure5;

Figure 7 is a partial plan view of the clamp construc tion of Figure 5;and

Figure 8 is a plan view of a bearing frame member which is adapted foruse with the clamp construction of Figure 5.

Referring now to Figure 1, there is shown an industrial truck, indicatedgenerally by the reference numeral 10, which has a pair of drivingwheels 11 disposed adjacent the forward end thereof and a pair ofsteeringwheels 12 disposed adjacent the rear end thereof. Mounted on theindustrial truck 10 is a drivers seat 13 and disposed at one sidethereof are a plurality of control levers, indicated generally by thereference numeral 14, which are provided for controlling the variousdevices of the industrial truck 10. Disposed adjacent the seat 13 is ahand steering wheel 15 which is mounted at the upper end of a steeringcolumn 16, operatively connected at its lower end to the rear steeringwheels 12.

Secured to the main frame of the industrial truck 10, adjacent theforward end thereof, is a substantially vertically extending mastconstruction, indicated generally by the reference numeral 17, which isof conventional construction and comprises a pair of outer fixed channelmembers 18, in which are slidably mounted a pair of inner channelmembers 19. The inner channel members 19 are interconnected, at theirupper ends, by a -The loadsupporting carriage of the industrial truck.10 provides a support for one form of clamp mechanism, of my presentinvention, indicated generally by refer-. ence numeral '25. Referringnow to Figures 2} 3," a'nd"4,"

Ishall describe in detail the construction of the clamp mechanism 25. Apairof vertically spaced transversely extending frame members 26 and 27are adapted to be secured to the load supporting carriage of theindustrial truck 10. A pair of vertically extending horizontally spacedframe members 28 have secured to their rear surfaces, adjacent the upperends thereof, hook-shaped brackets 29 which are disposed-over the upperedge of the upper transverse frame member 26. Also mounted, by bolts 30,to the vertical frame members 25, inter mediate of the ends thereof, arehook-shaped members 31 which are adapted to engage the lower surface ofthe upper transverse frame member 26. The hook-shaped members 29 and 31are thus adapted to securely mount the vertical frame members 28 totransverse frame member 26, while the lower portions of the verticalframe members 28 are adapted to bear against the lower transverse framemember 27. Suitablysecured to the forward surfaces of the vertical framemembers 28 is a plate member 32 which is provided with openings 33 forreceiving the heads of the aforementioned bolts 39. The ends of thetransversely extending frame members 26 and 27 are interconnected byvertical brace members 34.

Formed along the upper'edge of the plate member 32 is a forwardlyprojecting fixed clamp element 36. Also secured, as by welding, to theupper edge of the vertical transverse plate member 32, adjacent eachside thereof, are horizontal rearwardly extending L-shaped supportmembers 40. The support members 40 are reinforced by triangular braces41 which are suitably secured to the bottom surfaces of the supportmembers 40 and the rear surface of the vertical transverse plate member32. A rearwardly extending vertical guide plate member 42 is secured tothe upper surface of each of the support members 46, Mounted along theupper leading edge of the support members 40 are aligned triangularramps 44which, at their one ends, are secured to the vertical guideplate members 42. Mounted to the triangular ramps 44, along the angularfaces thereof, horizontally spaced fromthe guide plate members l2, areguide plate members 45.

Secured to the rearwardly extending legs of each of the L-shaped supportmembers 40 are a pair of vertical substantially triangular-shapedbracket members 46. The outer bracket 46 of each pair is secured, as bya plurality of bolts 47, to the support members 40, while the innerbracket 46 of each pair is suitably secured, as by welding, to thesupport members 40.

The rear ends of forwardly projecting hydraulic p'iston and cylinderassemblies, indicated generally by the reference numeral 48, aredisposed between each pair of brackets 46. Laterally extending pins 49are suitably secured to the cylinders 50 of the hydraulic piston andcylinder assemblies 48. The pins 49 are journaled in the verticalbracket members 46, adjacent the upper ends thereof.

The piston rods 51 of the hydraulic piston and cylinder assemblies 48have secured to their outer ends clamp members 52 which have downwardlyprojecting jaw elements 37. The leading edges of jaw elements 37 areformed with camming surfaces 38.

Each of the piston rods 51 of the hydraulic piston and cylinderassemblies 48 is provided with a vertically extending plate follower orcam member 53, which is mounted thereto, adjacent its upper end, bymeans of a pin member 54. The plate followers 53 are adapted to ride upthe angular surface of the triangular ramps 44 when the piston rod 51 isextended.

I shall now describe the operation of the embodiment of the clampconstruction of my present invention shown inFigures 1 through 4. Inpractice, when it is desired to transport a container, as, for example,a crate, having a suitable rim, bead, or chime 39, the industrialtruck'10 is maneuvered into a position where the vertical transverseplate member'32'is disposed closely'adjacent the crate to lever'oftheigroup-at '14, the load supporting carriage of the industrial truck10 is shifted vertically until the movable clamp members 52 are disposedclosely adjacent the upper edge of the crate to be picked up. Thenanother lever of the group at 14 is actuated so as to admit fluid underpressure to the closed end of the cylinders 50, thereby causing thepiston rods 51 to be extended. Extension of the piston rods 51 causesthe lower camming edges 33 of the movable clamp members 52 to engagewith the leading edge of the bead 39 of the crate, thereby causing thejaw elements 37 to move upwardly until the lower edges of the latterclear the upper edge of the bead 39 of the crate and drop into placebehind the rim or bead 39 thereof.

After the clamp members 52 have been disposed about the rim or bead 39of the crate, fluid under pressure is admitted to the forward ends ofthe cylinders 50 while fluid is bled from the closed ends of thecylinders 50, thereby causing the piston rods '51 to be retractedtowards the industrial truck 10. This causes the rim or bead 39 of thecrate to be urged toward the truck 10 until the rim 39 is securelyclamped between the jaw elements 37 of the movable clamp members 52 andthe fixed clamp element 36,as shown in Figure 3. By actuating one of thesuitable control levers at 14 the load supporting carriage maybe raised,which effects raising of the crate from the ground. The crate is thensupported at its upper end by the jaw element 37 and clamp element 36,and at its lower end is adaptedto bear against the vertical transverseplate member 32. The truck 10 may then be driven to the locationwhere-it is desired to deposit the crate. The reverse procedure is thenfollowed. That is, the load supporting carriage is lowered in the mastuntil the crate engages the ground, whereupon fiuid under pressure isadmitted to the closed ends of the cylinders 50 of the hydraulic pistonand cylinder assemblies 48, thereby causing the piston rods 51 and themovable clamp members 52 to be thrust outwardly. During outward'movementof the piston rods 51, theguide plate membersi53 are adapted to rideupwardly on the incline surfaces of the triangular ramps 44 causing thehydraulicpiston and cylinder assemblies 48 and movable clamp members 52to rotate clockwise about pin members 49, as viewed in Figure 3, whichraises the jaw elements37 .of the movable clamp members 52 above theupperedge of the chime or rim 39 of the crate deposited. The truck 10may then be backed away.

I shallnow describe, in connection with Figures 5, 6, 7, and 8, animproved form and preferred embodiment of clamp construction of mypresent invention.

The preferred form of clamp mechanism of mypresent invention comprisesone or more clamp constructions, each of which comprises a verticallyextending supporting plate member 70 and a clamp assembly, indicatedgencrally by the reference numeral 71. The supporting plate member 70has secured to its rear surface a hook-shaped bracket 72 which isadapted to be disposed over the upper edge of a transversely extendingframe member 73, adapted to be secured to the load supporting carriageof an industrial truck. The supportingplate member 70 also hassecured toits rear surface a hook-shaped member 74 which is adapted to engage thelower edge of the aforementioned frame member 73. A mounting bolt 76 isthreaded through the hookshaped bracket 72 and is adapted to be placedin engagement with the upper surface of thef rame member 73 for rigidlymounting the plate member 70 to the latter. A transverse frame member 75is also adapted to be secured tothe load supporting car riage of theindustrial truck, against which .frame member 75 the lower portion ofthe supporting plate member 70 is adapted to bear. The frame members 73and 75 'are similar in construction to the aforementioned frame members26 and 27.

'Two'sets of 'vertically'spaced key hole'slots 77 and 78 are formed inthe vertical supporting plate member 70, adjacent the upper andintermediate portions thereof.

Each of the clamp assemblies 71 comprises a vertically extendingbox-like frame structure comprising a rear plate member 79 and a pair offorwardly extending horizontally spaced side plate members 80 and 81. Apair of locating pins 82 are suitably secured in openings formed in therear plate member 79 of the clamp assembly 71. The enlarged headportions of the locating pins 82 are adapted to be disposed through theenlarged portions of the key hole slots 77 and then urged downwardly formounting the rear plate member 79 to the supporting plate member 70.

The rear plate member 79 is also secured to the supporting plate member77 by means of a locking bolt 83 which has a threaded end adapted to bedisposed through an opening formed in the rear plate member 79 and to bethreaded into engagement with a threaded opening formed in thesupporting plate member 70.

The forward edges of the side plate members 80 and 81 are interconnectedadjacent their upper and lower ends. respectively, by verticallyextending fixed clamp elements 84 and 85. Pivotally mounted intermediatethe side plate members 80 and 81, about a pin member 86, is the cylinder87 of a hydraulic piston and cylinder assembly, indicated generally bythe reference numeral 88. The cylinder 87 is maintained in a centralposition by spacer members 68. The hydraulic piston and cylinderassembly 88 has a piston rod 89 which, at its upper end, is pivotallymounted about a pin member 90 fixed at its ends within the dependinglegs of a triangular bell crank 91. The bell crank 91 is pivotallymounted about a pin member 92 which is fixed at its ends in the sideplate members 80 and 81 of the clamp assembly 71. The bell crank 91 ismaintained in a central position by spacer members 67. Pivotally mountedto the upper end of the bell crank 91, about a pin member 93 whichextends laterally outwardly of the sides of the bell crank 91, are therear ends of the spaced legs of a movable clamp element having a downwardly projecting forward jaw portion 69. Side frame members 95 aredisposed on each side of the movable clamp element 94 and are secured,respectively, to the side plate members 88 and 81 for guiding themovable clamp element 94 in substantially rectilinear movement.

When the clamp assembly 71 is secured in the position shown in Figure 6,an H-shaped bearing frame member 96 is adapted to be secured to thesupporting plate member 70 by means of a pair of locating pins 97adapted to be disposed in the key hole slots 78 formed in theintermediate portion of the vertically extending supporting plate member70. The bearing plate member 96 is provided in order that the lowerportion of a crate or container may bear against the latter When grippedbetween the clamp elements 94 and 84.

If it is desired to utilize the clamp assembly 71 for gripping a cartonor container of low height, the clamp assembly 71 may be removed fromthe upper portion of the supporting plate member 77 by unloosening thelocking bolt 83 and removing the locating pins 82 from the key holeslots 77 and thence disposing the locating pins 82 within theintermediate key hole slots '78 and again locking the lock bolt 83. Ifthe clamp assemblies 71 are to be used in this position, the bearingframe members 96 are removed.

I shall now describe, in connection with Figures 5, 6, 7, and 8, theoperation of the preferred form of clamp mechanism of my presentinvention.

One or more supporting plates 70 and associated clamp assemblies 71 maybe secured to the load supporting carriage of the industrial truck, theprecise number depending on the load carrying capacity required. Forexample, as shown in Figure 5, a pair of clamp assemblies 71 may besecured to the load supporting carriage. In picking up or engaging acontainer, the truck is maneuvered so as to dispose the pair of clampassemblies 71 closely adjacent the container. The truck is then drivenforwardly until the jaw portions 69 of the movable clamp members orelements 94 engage the leading edge of the rim, bead or chime of thecarton or container to be picked up. Further movement of the industrialtruck towards the container to bepicked up causes the jaw portions 69 ofthe movable clamp elements 94 to ride over the upper edge of the rimportion of the container and down into engagement with the rear edgethereof.

Fluid under pressure is then selectively admitted to the closed ends ofthe hydraulic piston and cylinder assemblies 88 which causes the pistonrods 89 to be extended. When the piston rods 89 are extended, the bellcranks 91 are caused to rotate counterclockwise about the mounting pinmembers 92 which causes the movable clamp elements 94 to be retractedtoward the industrial truck, thereby clamping the bead or rim portion ofthe container between the jaw portions 69 of the movable clamp elementsand the fixed clamp elements 84. After the container has been securelyvgripped, the load supporting carriage of the industrial truck may beraised and the container delivered to the desired location.

When the industrial truck has been aligned with the space in which thebox is to be deposited, the load supporting carriage is lowered untilthe carton contacts the ground. Then hydraulic fluid under pressure isadmitted to the upper ends of the cylinders 87 of the hydraulic pistonand cylinder assemblies 88, causing the piston rods 89 to be retracted.When the piston rods 89 are retracted, the bell cranks 91 are caused tobe rotated clockwise about the pin members 92, thereby urging themovable clamp elements 94 away from the industrial truck and releasingthe rim or chime portion of the container. The load supporting carriageof the industrial truck is then raised until the downwardly projectingjaw portions 69 of the movable clamp elements 94 clear the upper edge ofthe rim portion of the container, after which the truck 10 may be backedaway.

While I have shown and described what I believe to be certain preferredembodiments of my present invention, it will be understood that variousmodifications and rearragements may be made therein without departingfrom the spirit and scope of my present invention.

I claim 1. For use with an industrial truck having a mast and a loadsupporting carriage movable therealong, load engaging means comprising,frame means adapted to be mounted to the load supporting carriage, afixed clamp element carried by said frame means, substantiallyhorizontally movable clamp means carried by said frame means, hydraulicpiston and cylinder assembly means having the lengthwise axis thereofdisposed substantially vertically carried by said frame means, andmotion transmitting means connecting said hydraulic piston and cylindermeans and said movable clamp means.

2. For use with an industrial truck having a mast and a load supportingcarriage movable therealong, load engaging means including at least oneclamp assembly comprising, a substantially vertically extending box-likeframe means adapted to be carried by the load supporting carriage, forrectilinear vertical movement and defining a fixed clamp element, asubstantially horizontally movable clamp element disposed at the upperend of said frame means, actuator means disposed within the confines ofsaid frame means, and motion transmitting means joining said actuatormeans with said movable clamp element for moving said movable clampelement rectilinearly toward and away from said fixed clamp element.

3. The combination of claim 2 wherein said actuator means comprises ahydraulic piston and cylinder assembly and said motion transmittingmeans comprises a bell crank means between said hydraulic piston andcylinder assembly and said movable clamp element.

4. For use with an industrial truck having a mast and a load supportingcarriage movable therealong, load engaging means including at least oneclamp assembly

